Blocked checkvalve or stuck in the open position? Blocked & you won't be able to turn with the wheel or pilot because a check valve is in-line. Open with perhaps a piece of debris under the valve & yes, your assumption would be correct.
Try really ,REALLY giving the wheel a hard, snapping turn in both directions. That'll dislodge a piece on trash from under a valve in lots of cases.
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-Shawn-
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